Now that Peter Jackson seems to be lost in Middle Earth until further notice, Guillermo del Toro is the most lovably rabid fan of monsters that cinema has.

I like to imagine del Toro as a kid, slathering paint on his Aurora monster models, devouring dog-eared issues of Famous Monsters, and staging epic fights between his toy robots and his toy monsters, going “Rrrrgh” and “Dssssh” and other clash-of-the-plastic-titans sound effects that little kids vocalize. Unlike a hack like Michael Bay, who was only in the Transformers movies for the money, del Toro lives and breathes this stuff like mythopoetic oxygen.

Pacific Rim, his first directing gig in five years, follows the blueprint of his other semi-mainstream stuff like Blade II and the two Hellboy films — it’s loud and bombastic, with copious imagination and perversity snuck through a side door. Time will tell if del Toro is still interested in making smaller, more intimate masterpieces like Cronos, The Devil’s Backbone or Pan’s Labyrinth, but at least here he shows he can play the game. Pacific Rim is del Toro back in his childhood bedroom, slamming his toys together in a gleeful death match. In one corner you have the kaiju, gigantic sea monsters who slither ashore and decimate entire cities. In the other corner you have the jaegers, gigantic mechas steered by two pilots joined by neural “drift.” Whenever a kaiju shows up — and they’re starting to show up with greater frequency — the jaegers drop in via helicopter and punch the everloving shit out of the kaiju. Rrrrgh! Dssssh!

There’s a bit of what, these days, is forlornly called “the human element” here. Raleigh Becket (Charlie Hunnam) is a former master jaeger pilot, inactive for five years following the death of his brother and jaeger partner. Raleigh mopes around in construction — the world’s leaders have unwisely decided to build walls against the kaiju instead of continuing with the jaeger program — until his commanding officer, Marshal Stacker Pentecost (Idris Elba), pulls him back in. Raleigh teams up with newbie pilot Mako Mori (Rinko Kikuchi), who as a girl lost her family in a kaiju attack on Tokyo. There are other humans, like scientists Charlie Day (a kaiju enthusiast) and Burn Gorman (a mathematician), and various jaeger masters from different countries — it’s almost an Olympics of dragonslayers — and the highly amusing Ron Perlman as Hannibal Chau, who salvages kaiju organs and does a brisk black-market business out of Hong Kong.

But the script, credited to del Toro and Travis Beacham, isn’t overly convoluted; the filmmakers know why we’re there, and it isn’t necessarily to see the friction between Raleigh and a hotshot young Aussie pilot. No, we’re there to see rrrrgh and dssssh, and del Toro gives it to us on a massive scale, often with a rising line of adrenaline that translates in the awestruck moviegoer’s mind as “Holy fuckin’ SHIT.” Pacific Rim brings the wow and the chthonic thunder on a level that no other blockbuster this summer has managed. Still, del Toro is human, and he tosses in little gags and asides; a bit involving an executive desk toy stands out in my memory. The movie is rapturously sincere but never takes itself too seriously. At its peak efficiency it’s one king-hell good earth-shaking time.

And yet ... I miss the del Toro who found beauty in all the rugose freaks in the Hellboy films, who wove tapestries of frightened good and nightmarish evil in his foreign-language films. The same anticipatory excitement that draws some of us to a giant-robot-vs.-giant-monster epic directed by Guillermo del Toro — how could it not be the awesomest thing ever? — ultimately leads to a bit of a letdown when it isn’t, in fact, the awesomest thing ever, but just relatively awesome: awesome relative to the movies that got it wrong (ahem, Transformers) and relative to the mostly wan franchise place-holders preceding it this season. If Pacific Rim, as del Toro intended, fires up kids’ imaginations and sends them running off to the better old Toho monster mashes or to the more recent Gamera films of the ’90s, it was money well spent.

It’s not really meant to appeal to us older del Toro fans, who know he’s capable of richer and darker dreams; it’s for the boys and girls building creatures in their bedrooms, who will look at "Pacific Rim," the way del Toro looked at "Gojira" or "King Kong," and say “I wanna do something like that when I grow up. I wanna build that world, make that happen. Rrrrrgh. Dssssh.”